Visualisation and Three Dimensional Presentation in Orthopaedics and Traumatology

Abstract

Since the discovery of the X-ray, sagittal and frontal tomography has been introduced to medical practices, for more exact definitions of opacities for survey radiographs. These tomographies occur by only highlighting a particular area of the body and blurring the background through smear techniques. A computer supported evaluation, such as a tumour volume assessment, is however very inadequately predictable by this method. Only since the conception of X-ray-computer tomography at the beginning of the 1970’s has it been made possible, to further process x-rays digitally. The rotational tomography equipment used today, consist of a fanbeam whose radiation angle is so concipated that it encompasses the whole body section. The weekend rays are taken from a respectively large detector array (more than 500 monitoring probes) simultaneously /1/. A higher speed, with equivalent mechanical stability, is supplied by tomography equipment of the fourth generation, by which a 360 degree fixed assembled set of detectors (over 1000 monitoring probes) radiographs the rays from the X-ray tube rotating around the body. With dedicated hardware and special image reconstruction algorithms (Radon Transformation or Back Projektion) the sectional image of the radiated layer from the low intensity samples is calculated within approximately 1–3 secs. The local resolution of these radiographs is typically 256·256 pixels or even 512·512 pixels. The image halftone resolution is 12 bit /15/.